Soil organic carbon (SOC) plays a vital role in the productivity and resilience of terrestrial ecosystems, particularly in arid regions like Iran's central plateau, where carbon stocks are low and vulnerable to degradation. This study modeled the organic carbon pool (OCpool) in Mehrgard Catchment, Semiroum County (1275.59 km2), a representative arid landscape, using a Generalized Linear Model (GLM) to identify key environmental drivers. The GLM, with an R-2 of 0.622 revealed that dynamic factors, normalized difference vegetation index (NDVI) and land surface temperature (LST), and static factors like slope (SLP) primarily influence OCpool variability. Specifically, NDVI during peak growth (NDVImax, p < 0.001) strongly increased OCpool by enhancing organic matter inputs, while LST at minimum and maximum levels (LSTmin, p = 0.001; LSTmax, p = 0.004) reduced OCpool by accelerating microbial decomposition. Valley depth (VDP, p = 0.005) also decreased OCpool through erosion, and SLP showed a borderline effect (p = 0.049). Other topographic factors, such as distance to stream and convergence index, had minimal impact. These findings highlight the dominance of vegetation and temperature over terrain in arid SOC dynamics, emphasizing the need for land management practices like rotational grazing to protect NDVI, alongside terracing to stabilize SLP, to mitigate SOC loss in arid ecosystems.